A screw compressor includes a male rotor and a female rotor rotating in engagement with each other and a casing that accommodates the male rotor and the female rotor. Generally, the male rotor and the female rotor each include shaft sections on two sides thereof and the shaft sections on the two sides are rotatably supported by bearings held in the casing.
Differently from the screw compressor of this structure, there is known a screw compressor configured such that holes are provided in end surfaces of two sides of each of a male rotor and a female rotor and bearings are held in these holes (refer to, for example, Patent Document 1). The screw compressor described in Patent Document 1 has a structure such that a suction-side bearing casing and a discharge-side bearing casing that constitute a part of a casing include support journals entering holes in which the male rotor and the female rotor are held, and that those support journals support the male rotor and the female rotor.